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31.
本文对辽宁地区6个输油管道段两侧10km范围内的断层活动性进行了研究,其中有5条晚更新世-全新世断裂与管道相交,交叉点共有8处。在此基础上,重点研究了跨断层输油管道的震害特点,给出了不同地震烈度下剪切与弯曲破坏概率及震害预测结果。  相似文献   
32.
古气候模拟     
古气候模式与现代气候模式控制因子不完全相同,有的因子在现代气候模拟中可以不考虑,但是在古气候模拟中则是必不可少的,例如轨道参数、大气中温室气体的浓度、大陆冰盖、大洋热盐环流等。而且,随着模拟的时间尺度不同,这些因子的作用也不同。评价古气候模拟,可以从3处着眼:气候变化的方向、幅度和速度。但是,长期以来古气候模拟仅仅涉及到前两个问题,也就是研究气候对外强迫的平衡响应。集其大成者是古气候模式比较计划(Paleaoclimate Modelling Intercomparison Project,  相似文献   
33.
Simplified techniques based on in situ testing methods are commonly used to predict liquefaction potential. Many of these simplified methods are based on finding the liquefaction boundary separating two categories (the occurrence or non-occurrence of liquefaction) through the analysis of liquefaction case histories. As the liquefaction classification problem is highly nonlinear in nature, it is difficult to develop a comprehensive model taking into account all the independent variables, such as the seismic and soil properties, using conventional modeling techniques. Hence, in many of the conventional methods that have been proposed, simplified assumptions have been made. In this study, an updated support vector machine (SVM) based on particle swarm optimization (PSO) is used to evaluate liquefaction potential in two separate case studies. One case is based on standard penetration test (SPT) data and the other is based on cone penetration test (CPT) data. The SVM model effectively explores the relationship between the independent and dependent variables without any assumptions about the relationship between the various variables. This study serves to demonstrate that the SVM can “discover” the intrinsic relationship between the seismic and soil parameters and the liquefaction potential. Comparisons indicate that the SVM models perform far better than the conventional methods in predicting the occurrence or non-occurrence of liquefaction.  相似文献   
34.
People living in the urban area and the surrounding suburban area have disparities in exposure and health risks due to different levels of ambient air pollutants. The main objective of this study is to investigate the concentrations, seasonal variations, and related health risks of ambient air pollutants (PM10, NO2, and SO2) in urban and suburban areas of Ningbo, China. The results showed that the average PM10, NO2, and SO2 concentrations in the urban area were 85.2, 49.3, and 37.4 μg/m3, which were 1.13, 1.25, and 1.41 times the values of the suburban area during the period of March 2009 to February 2010. For the potential health risk analysis, the residents have been divided into four age categories namely, infants, children (1 year), children (8–10 years), and adults. The analysis took into account age-specific breathing rates, body weights for different age categories. The results showed that the potential health risks to respiratory disease for all age categories living in urban area were higher than those in suburban area.  相似文献   
35.
Dated isotopic ages for 15 alkaline intrusives in the Yanliao-Yinshan area, ranging from 268 to 190 Ma, ten of which are from 250 to 208 Ma, indicate that most of them were formed in the Triassic Epoch. All the ENd(t) ratios from - 17.19 to -3.21 averaging -7.09, the ESr(t) ratios fmm 11.7 to71.5 averaging 36.63, and the Isr(t) ratios from 0.705 0 to 0.709 3 averaging 0.706 8, show their characteristics of enrichment. On the ENd (t) virus ESr(t) correlation diagram, the samples from these intmsives were plotted within the enriched mantle trend lines and just outside, demonstrating their close connection to materials from the enriched mantle reservoir, taking into account the same Pb isotopic composition as that of the mantle.  相似文献   
36.
Geochronology of the volcanic rocks in the Lu-Zong basin and its significance   总被引:23,自引:0,他引:23  
The Lu-Zong (Lujiang-Zongyang) basin is one of the most important volcanic basins in the middle and lower reaches of the Yangtze River area, China. It comprises four shoshonitic volcanic units, which are, in an ascending order, the Longmenyuan, Zhuanqiao, Shuangmiao and Fushan Groups. The LA-ICP MS U-Pb zircon ages of the four units are: 134.8±1.8 Ma for the Longmenyuan Group, 134.1±1.6 Ma for the Zhuanqiao Group, 130.5±0.8 Ma for the Shuangmiao Group, and 127.1±1.2 Ma for the Fushan Group. The results indicate that all volcanic rocks in the Lu-Zong basin were formed in the Early Cretaceous from about 135 Ma to 127 Ma, lasting 8-10 Ma. There were no Jurassic volcanic activities in all the volcanic basins including the Lu-Zong basin in the middle and lower reaches of the Yangtze River area. This work has provided new chronological results for the further study and understanding of the tec- tonic, magmatic and metallogenic processes of eastern China in the Mesozoic.  相似文献   
37.
从昭通地震破坏实例看山区地震地面破坏特点   总被引:4,自引:0,他引:4       下载免费PDF全文
1974年5月11日3时25分,东经104度,北纬28.2度我国云南省昭通境内发生M=7.1地震。宏观震中为大关县以北,木杆公社钟(杜)家坪附近。震中烈度为IX度。震区为拔海2000米的滇东北高原地区,地面经受强烈切刻,山高坡陡,尤其震区西部,地形尤显陡峻。地形的坡度一般均在30°以上,主要河流的坡降平均为2.53%。该区地质情况比较复杂。地层分布主要为二迭纪阳新统灰岩,峨眉山玄武岩,三迭纪飞仙关砂页岩等等。  相似文献   
38.
地质雷达快速检测运营公路隧道隐患   总被引:4,自引:0,他引:4  
为了评价运行多年隧道的衬砌质量,查找隐患,开展了拱顶的地质雷达无损快速检测。在雷达波形剖面图上分析空洞、不密实异常,推断出大量隐患。物探成果经过开凿验证,证明其隐患定位成功率在85%以上。地质雷达快速检测方法为隧道病害治理提供了可靠的基础资料。  相似文献   
39.
40.
多级速度梯度的建立理论上可为絮体的成长创造更理想的环境。目前对流化床混凝工艺的研究多是基于单级速度梯度开展的。以粒径为800 μm 和1 200 μm的树脂颗粒为固相,建立多级速度梯度流化床混凝装置,探讨絮体的成长与形态特征。研究结果表明:在单级速度梯度流化床混凝装置中,当以1 200 μm树脂颗粒为固相颗粒、混凝时间为50.3 s时,絮体发生破碎,混凝效率较混凝时间为41.8 s时降低3%;相同初始填充高度的多级速度梯度条件下,絮体尺寸随着混凝时间的延长而逐渐增加,由5.7 μm成长至70.0~75.0 μm,同时混凝效率也较单级速度梯度下提高了5%~10%。絮体之间的碰撞为絮体成长的主要模式。  相似文献   
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